Lanyards and key chains are widely available for holding small portable devices, badges and keys. Stretchable lanyards and key chains typically comprise a helically coiled cord made of metal or plastic. The cord has two ends. One end of the cord is connected to the user's belt or pocket and the other end is connected with a key or a small portable item. The cord is stretchable by way of partially straightening the helical coils so that the item to be carried can be used while always remaining connected with the user's belt or pocket.
The problem with this type of lanyard or key chain is that it is very inconvenient to travel with a long helically coiled cord. It can be dangerous and cumbersome if the cord is caught, for example, by a machines or a door knob. Also, the jangling of the cord can be rather disturbing.